Re: [rtcweb] JSEP-19: Impact of BYE on ssrc table (Appendix B)

This makes sense to me. Alternatively, we could leave the flag as an
implementation detail, and simply say to cull dynamically created entries
upon receiving a BYE:

      If the packet is of type BYE, it indicates that the RTP streams
      referenced in the packet are ending.  Therefore, for each SSRC
      indicated in the packet that is found in the incoming SSRC table,
      first deliver a copy of the packet to the "m=" line associated
      with that SSRC, *and, if it was created dynamically via receipt*

*      of a RTP or RTCP packet*, remove the entry for that SSRC from the

      incoming SSRC table.

On Fri, Mar 10, 2017 at 2:31 PM, Bernard Aboba <bernard.aboba@gmail.com>
wrote:

> In the algorithm described in Appendix B, SSRCs that are entered into the
> SSRC table due to signalling are not distinguished from those that are
> "latched" into the table dynamically.
>
> The distinction is important because only "latched" SSRCs should be
> removed due to receipt of a BYE (or a timeout).
>
> My suggestion of how to address this is to add a "D" flag to an SSRC table
> entry, indicating that the entry was added dynamically.
>
> For example:
>
>       If the packet has a MID, and the packet's extended sequence number
>       is greater than that of the last MID update, as discussed in
>       [RFC7941], Section 4.2.6 <https://tools.ietf.org/html/rfc7941#section-4.2.6>, update the incoming SSRC mapping table
>       to include an entry [with the "D" flag set] that maps the packet's
>       SSRC to the "m=" line for that MID.
>
>
> Also:
>
>       If the packet's payload type is in the payload type table, update
>       the the incoming SSRC mapping table to include an entry
>
>       [with the "D" flag set] that maps the packet's SSRC to the "m="
>
>       line for that payload type.  In addition, route the packet to the
>
>       associated "m=" line and stop.
>
>
> Then when a BYE is received, check the "D" flag:
>
>
>       If the packet is of type BYE, it indicates that the RTP streams
>       referenced in the packet are ending.  Therefore, for each SSRC
>       indicated in the packet that is found in the incoming SSRC table,
>       first deliver a copy of the packet to the "m=" line associated
>       with that SSRC, but then [if the "D" flag is set] remove the
>
>       entry for that SSRC from the incoming SSRC table.
>
>
>
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